: Ring rolling process is a forming process that used for producing seemless rings that had accurate dimension tolerances. This process needs less primary material compared with forging, and is able to produce most of open section rings in any quantity and dimensions. So according to the above adventages, ring rolling process is the mai processes in manufacturing large ring parts like wind electric power generating tower flange. The main goal of this dissertatio is to use finite element method for simulating radial- axial ring rolling procees for large rings and finally determination of main parts of this process. The process is simulated in ABAQUS commercial software and with this simulation in this software, forces that acts on parts were obtained. In these simulations, initial and boundry conditions proportional to practical conditions were considered. According to volume of calculations that need for contact between rolls and ring, we used thermal spokes instead simulation of guide rolls for circulating of ring. absence of the guide rolls in the FE simulation of the ring rolling process leads to the deflection of the ring during the process and eventually suspending the simulation. Typical simulation were done for verifying utilized method. And compared with results found in the literature which good agreement. Also thermal spokes method were used for simulating non rectangular sections like L- shape. It should be mentioned that this simulation is according to primary design of blank, diameter and velocity of rolls. Also influence of the main roll and the mandral diameter and the cone angle of the axial roll on the radial and the axial force and torque was perused. Finally, main parts of ring rolling machine were determined according to simulation outputs such as forces and torques. Key words: Radial- axial ring rolling process, finite element method, thermal spokes, designing of main parts of process
